US7247985B2 - Semiconductor light-emitting device having annular shape light emitting region and current blocking layer - Google Patents

Semiconductor light-emitting device having annular shape light emitting region and current blocking layer Download PDF

Info

Publication number
US7247985B2
US7247985B2 US10/969,015 US96901504A US7247985B2 US 7247985 B2 US7247985 B2 US 7247985B2 US 96901504 A US96901504 A US 96901504A US 7247985 B2 US7247985 B2 US 7247985B2
Authority
US
United States
Prior art keywords
light
current
emitting
layer
region
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active, expires
Application number
US10/969,015
Other versions
US20050093428A1 (en
Inventor
Kazuaki Kaneko
Hiroshi Umeda
Kazuaki Sasaki
Junichi Nakamura
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Xiamen Sanan Optoelectronics Technology Co Ltd
Original Assignee
Sharp Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sharp Corp filed Critical Sharp Corp
Assigned to SHARP KABUSHIKI KAISHA reassignment SHARP KABUSHIKI KAISHA ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: KANEKO, KAZUAKI, NAKAMURA, JUNICHI, SASAKI, KAZUAKI, UMEDA, HIROSHI
Publication of US20050093428A1 publication Critical patent/US20050093428A1/en
Application granted granted Critical
Publication of US7247985B2 publication Critical patent/US7247985B2/en
Assigned to XIAMEN SAN'AN OPTOELECTRONICS CO., LTD. reassignment XIAMEN SAN'AN OPTOELECTRONICS CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: SHARP KABUSHIKI KAISHA
Active legal-status Critical Current
Adjusted expiration legal-status Critical

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/14—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a carrier transport control structure, e.g. highly-doped semiconductor layer or current-blocking structure
    • H01L33/145—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a carrier transport control structure, e.g. highly-doped semiconductor layer or current-blocking structure with a current-blocking structure
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/484—Connecting portions
    • H01L2224/48463—Connecting portions the connecting portion on the bonding area of the semiconductor or solid-state body being a ball bond
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/30—Technical effects
    • H01L2924/301—Electrical effects
    • H01L2924/3025—Electromagnetic shielding

Definitions

  • the present invention relates to a semiconductor light-emitting device, and more particularly, to a semiconductor light-emitting device in which a light-emitting region provided on a surface of light-extraction side of the device has an annular shape.
  • FIGS. 8 and 9 are a plan view and sectional view of a conventional semiconductor light-emitting device, respectively.
  • FIG. 10 is an explanatory view illustrating a light-emitting state of the conventional semiconductor light-emitting device (see, for example, Japanese Unexamined Patent Publication No. HEI 4(1992)-229665).
  • a semiconductor light-emitting device 21 includes: a substrate 23 having an electrode 22 formed on its rear surface, and a lower cladding layer 24 a , an active layer 25 , an upper cladding layer 24 b , a current-spreading layer 29 and an electrode 30 formed in this order on the substrate 23 .
  • the lower cladding layer 24 a , active layer 25 and upper cladding layer 24 b constitute a light-emitting region layer (light-emitting layer) 26 .
  • the light-emitting device 21 further includes, in a central region of the current-spreading layer 29 , a current-blocking layer 28 formed on the light-emitting region layer 26 side of the layer 29 .
  • the current-blocking layer 28 is formed at a position where it opposes the electrode 30 located on the current-spreading layer 29 .
  • FIGS. 11 and 12 are a plan view and sectional view of another conventional semiconductor light-emitting device, respectively.
  • FIG. 13 is an explanatory view illustrating a light-emitting state of the conventional light-emitting device (see, for example, Japanese Unexamined Patent Publication No. HEI 11(1999)-26810).
  • a semiconductor light-emitting device 41 includes: a substrate 43 having an electrode 42 formed on its rear surface, and a lower cladding layer 44 a , an active layer 45 , an upper cladding layer 44 b , a current-spreading layer 49 and an electrode 50 formed in this order on the substrate 43 .
  • the lower cladding layer 44 a , active layer 45 and upper cladding layer 44 b constitute a light-emitting region layer (light-emitting layer) 46 .
  • the light-emitting device 41 further includes, in an outer region of the current-spreading layer 49 , a current-blocking layer (current-narrowing layer) 48 formed on the light-emitting region layer 46 side of the layer 49 .
  • the electrode 50 has an opening in the center thereof and is formed at a position where it opposes the current-blocking layer 48 .
  • the structure shown in FIGS. 11 to 13 requires a wire-bonding area 51 to be provided in a corner of the device.
  • the wire-bonding area 51 usually needs a diameter of about 90 ⁇ m, and this obstructs reduction in device size.
  • the present invention provides a semiconductor light-emitting device in which the density of current introduced into the light-emitting layer is increased to improve the luminous intensity and to achieve uniform light-emission, and in which wire-bonding area is not required and hence, miniaturization of the device is possible.
  • a semiconductor light-emitting device comprises: a semiconductor substrate; a light-emitting layer formed on the semiconductor substrate; a current-blocking layer formed on a part of the light-emitting layer for restricting light-emission; a current-spreading layer formed on the current-blocking layer and the other part of the light-emitting layer; a front electrode formed on the current-spreading layer; and a rear electrode formed on a rear side of the semiconductor substrate, wherein the current-blocking layer is composed of a central region and an outer region which surrounds the central region via a part of the current-spreading layer, so that a light-emitting region that appears on a front surface of the device has an annular shape, and the front electrode and the central region of the current-blocking layer are opposed to each other.
  • the current-blocking layer comprises the central and outer regions, so that the light-emitting region that appears on the front surface of the device is defined between the central and outer regions to have an annular shape. This allows for improved luminous intensity over devices that do not include the outer region of the current-blocking layer, and for uniform light-emission.
  • the semiconductor light-emitting device can be miniaturized.
  • FIG. 1 is a plan view illustrating the general construction of a semiconductor light-emitting device according to a first example embodiment
  • FIG. 2 is a sectional view of the device of FIG. 1 ;
  • FIG. 3 is an explanatory view illustrating a light-emitting state of the top of the device of FIG. 1 ;
  • FIG. 4 is a plan view illustrating the general construction of a semiconductor light-emitting device according to another example embodiment
  • FIG. 5 is an explanatory view illustrating a light-emitting state of the top of the device of FIG. 4 ;
  • FIG. 6 is a graph illustrating a relationship between the width of a light-emitting region (annular opening) of the device according to the present invention and the ratio of the luminous intensity of the device according to the first embodiment to that of a conventional light-emitting device;
  • FIG. 7 is a graph illustrating a relationship between the ratio of maximum to minimum values of the width of a light-emitting region (annular opening) of the device according to the present invention and the ratio of the luminous intensity of the device according to the second embodiment to that of the conventional semiconductor light-emitting device;
  • FIG. 8 is a plan view illustrating the general construction of a conventional semiconductor light-emitting device
  • FIG. 9 is a sectional view of the device of FIG. 8 .
  • FIG. 10 is an explanatory view illustrating a light-emitting state of the top of the device of FIG. 8 ;
  • FIG. 11 is a plan view illustrating the general construction of another conventional semiconductor light-emitting device.
  • FIG. 12 is a sectional view of the device of FIG. 11 ;
  • FIG. 13 is an explanatory view illustrating a light-emitting state of the top of the device of FIG. 11 .
  • a semiconductor light-emitting device comprises: a semiconductor substrate; a light-emitting layer formed on the semiconductor substrate; a current-blocking layer formed on a part of the light-emitting layer for restricting light-emission; a current-spreading layer formed on the current-blocking layer and the other part of the light-emitting layer; a front electrode formed on the current-spreading layer; and a rear electrode formed on a rear side of the semiconductor substrate.
  • the semiconductor substrate may be any as long as the light-emitting layer (hereinafter also referred to as a light-emitting region layer) can be formed thereon.
  • the substrate preferably lattice-matches the light-emitting layer.
  • the substrate include substrates of compound semiconductors such as GaAs, GaN, GaP, InP, ZnO and ZnSe, and of elementary semicondutors such as Si and Ge.
  • the substrate may have n- or p-type conductivity.
  • the rear electrode may be referred to as a substrate-side electrode
  • the rear electrode may be formed of a conductive material, and preferably has an ohmic contact with the substrate.
  • the rear electrode may be formed of, for example, a metal such as Au, Pt, Al, Ni or Ti, or an alloy such as AlGe or AlZn.
  • a metal such as Au, Pt, Al, Ni or Ti
  • an alloy such as AlGe or AlZn.
  • an AlGe electrode is preferably used.
  • the rear electrode may be formed by, for example, forming a metal or alloy film by means of vapor deposition, sputtering or the like, followed by a heat treatment of the film.
  • the rear electrode may be formed on a side or rear surface of the substrate.
  • a contact layer for example, may be provided for obtaining an ohmic contact.
  • the light-emitting layer formed on the substrate may be any as long as it emits light by passing a current thereto.
  • the light-emitting layer preferably has a double heterojunction structure of a lower cladding layer, active layer and upper cladding layer, but may have a single heterojunction structure or homojunction structure.
  • Semiconductor layers that constitute the light-emitting layer may be formed of, for example, a compound semiconductor.
  • the compound semiconductor include a binary compound semiconductor such as GaAs, GaP or GaN, a ternary compound semiconductor such as AlInP, AlGaAs, GaAsP, InGaAs or InGaN, and a quaternary compound semiconductor such as InGaAsP or AlGaInP.
  • the composition of the compound semiconductor may be determined so as to obtain light of a desirable wavelength.
  • the composition of the compound semiconductor used for the active layer is determined so as to obtain light of a desirable wavelength.
  • the compositions of the lower and upper cladding layers are determined so that the band gaps thereof are greater than that of the active layer.
  • the light-emitting layer of any of the double heterojunction, single heterojunction or homojunction structure comprises two or more semiconductor layers.
  • the lowermost layer of the semiconductor layers has the same conductivity type as the substrate, and the uppermost layer of the semiconductor layers has a different conductivity type from the substrate.
  • the active layer of the double heterojunction structure may be undoped or doped with n-type or p-type impurities.
  • Each semiconductor layer that constitutes the light-emitting layer may be formed by a method such as LPE, MOCVD, MBE or MOMBE.
  • the semiconductor layer of n-type may be formed by doping Si, S, Se, Te or the like, and the semiconductor layer of p-type may be formed by doping Zn, Mg, C, Be or the like.
  • semiconductor layers such as the contact layer, a buffer layer, a cap layer, the current-blocking layer and the current-spreading layer which will be described later may be formed by similar methods.
  • the buffer layer may be provided for offsetting the difference in lattice constant.
  • the current-blocking layer is formed on a part of the light-emitting layer for restricting light-emission, and the current-spreading layer is formed on the current-blocking layer and the other part of the light-emitting layer.
  • the current-blocking layer may be any as long as it prevents, or makes difficult, the flowing of currents from the current-spreading layer to the light-emitting layer.
  • the current-blocking layer may be formed of, for example, a semiconductor which is doped with impurities of different conductivity type from the uppermost layer of the light-emitting layer or which has a small carrier concentration. Examples of such a semiconductor include GaP, AlGaP, AlGaAs and AlGaInP.
  • the current-blocking layer may also be formed of a semiconductor which has the same conductivity type as the uppermost layer of the light-emitting layer and which allows a heterobarrier formed between the current-blocking layer and the uppermost layer of the light-emitting layer to be greater than that formed between the current-spreading layer and the uppermost layer.
  • the uppermost layer of the light-emitting layer, current-blocking layer and current-spreading layer may be formed of p-type AlGaInP, p-type GaAs and p-type GaAlAs, respectively.
  • the current-spreading layer may be any as long as it spreads current fed from the front electrode.
  • the current-spreading layer is preferably formed of a material having a band gap greater than the energy of light generated in the light-emitting layer so that the light generated in the light-emitting layer is less absorbed. Further, the current-spreading layer is preferably formed of a material having a small resistivity so as to facilitate the current spreading.
  • the current-spreading layer may be formed of, for example, a compound semiconductor.
  • the compound semiconductor include a binary compound semiconductor such as GaP, a ternary compound semiconductor such as GaAlAs or InGaN, and a quaternary compound semiconductor such as AlGaInP or AlGaInN.
  • the current-spreading layer preferably has the same conductivity type as the uppermost layer of the light-emitting layer.
  • the current-blocking layer is composed of a central region and an outer region surrounding the central region via a part of the current-spreading layer, so that a light-emitting region that appears on a front surface of the semiconductor light-emitting device has a circular shape.
  • the current-blocking layer is formed on the light-emitting layer prior to the formation of the current-spreading layer.
  • the current-blocking layer is formed such that an annular opening is formed between its central and outer regions.
  • the annular opening may be formed by partially removing the current-blocking layer that is formed on the entire surface of the light-emitting layer by means of photolithography and etching.
  • the term “annular” used herein includes a circular shape, a polygonal shape, and a ring- or loop-shape obtained from a rounded polygon.
  • the “opening” is preferably a through hole, but may be a blind hole. Where the “opening” is a blind hole, a semiconductor which forms the current-spreading layer is filled in the annular opening, that is, between the central and outer regions.
  • annular current-flow-through region may be formed.
  • a semiconductor doped with impurities of different conductivity type from the uppermost layer of the light-emitting layer or a semiconductor having a small carrier concentration, such as GaP, AlGaAs or AlGaInp may be used to form the current-blocking layer.
  • impurities of the same conductivity type as the uppermost layer may be annularly diffused to form the annular current-flow-through region.
  • a semiconductor layer in which current can easily flow may be formed. Then, the layer may be doped with impurities of different conductivity type from the uppermost layer except for a portion to serve as the annular current-flow-through region.
  • the cap layer may be formed between the current-blocking layer and the light-emitting layer.
  • the cap layer may be formed of an oxidation-resistant material.
  • the cap layer may be formed of, for example, a material that does not contain aluminum, such as GaInP.
  • the cap layer may also be formed of a material having a small aluminum content.
  • the central region of the current-blocking layer and the front electrode (may also be referred to as a light-extraction side electrode) are opposed to each other.
  • the front electrode may be formed of a conductive material, and is preferably capable of forming an ohmic contact with the current-spreading layer.
  • the front electrode may be formed of, for example, a metal such as Au, Pt, Al, Ni or Ti, or an alloy such as AlGe or AlZn. Where the substrate is of p-type semiconductor, an AlZn electrode is preferably used.
  • the front electrode may be formed by, for example, forming a metal or alloy film by means of vapor deposition, sputtering or the like, and then processing the film into a desirable shape by photolithography and etching techniques, followed by heat treatment.
  • the front electrode may have any shape and size, and preferably has such shape and size that a wire-bonding area can be provided thereon.
  • the front electrode preferably has a circular shape, and a radius of 45 ⁇ m or greater so that a space for wire bonding is secured. In order to provide enough space therefor, it is more preferable that the front electrode has a radius of 50 ⁇ m or greater.
  • the contact layer formed of, for example, GaAs may be provided for obtaining an ohmic contact.
  • the current-blocking layer is composed of the central region and the outer region surrounding the central region via a part of the current-spreading layer so that a light-emitting region that appears on the front surface of the light-emitting device has an annular shape.
  • the outer contour (outer perimeter) of the front electrode is preferably set to have a size substantially equal to that of the inner contour (inner perimeter) of the light-emitting region or a size such that the outer contour of the front electrode falls within the inner contour of the light-emitting region (i.e., the outer contour of the front electrode is smaller than the inner contour of the light-emitting region). This is because, when the front electrode is larger than the inner contour of the light-emitting region, the light-emitting layer emits light under the front electrode, and the emitted light is shielded by the front electrode, preventing the light from being taken outside.
  • the outer contour of the front electrode is preferably set such that the width between the outer contour of the front electrode and the inner contour of the light-emitting region is substantially uniform. By doing so, driving current is uniformly fed into the light-emitting layer.
  • the light-emitting region preferably has a circularly annular shape and the front electrode preferably has a circular shape.
  • the difference in radius between the outer perimeters of the light-emitting region and the front electrode is preferably 7.1 to 10.7 times the thickness of the current-spreading layer.
  • the distance between the inner and outer perimeters of the light-emitting region, that is, the width of the light-emitting region is 25 ⁇ m or greater.
  • the ratio of the maximum to minimum values of this distance is preferably 1.4 times or smaller.
  • the radius of the inner perimeter of the circularly annular light-emitting region is preferably 1.3 to 1.7 times the radius of the outer perimeter of the front electrode. Where the ratio is less than 1.3, a highly-developed alignment technique is required at the formation of the front electrode, and thereby the production efficiency of the device decreases. Where the ratio is more than 1.7 times, the area of the device that does not contribute to light-emission increases, resulting in an increase in device area. This reduces the number of devices produced per unit area of a wafer.
  • the width of the annular light-emitting region is substantially uniform. By doing so, driving current is uniformly fed into the light-emitting layer.
  • the width of the annular light-emitting region is preferably 25 ⁇ m or greater as described above, and more preferably from 25 ⁇ m to 40 ⁇ m inclusive. Where the width is smaller than 25 ⁇ m, there is a fear that etching irregularities may be caused, which leads to a malfunction of the device. Where the width is larger than 40 ⁇ m, there is a fear that luminous intensity may decrease due to variations in current density in the light-emitting region.
  • the outer contour (outer boundary or outer perimeter) of the light-emitting region (annular opening ) is preferably 20 ⁇ m or more apart from the outer contour of the semiconductor substrate, and more preferably, from 15 ⁇ m or more to 40 ⁇ m or less apart from the outer contour of the substrate. Where the distance between the two is less than 15 ⁇ m, there is a higher possibility of cutting the annular opening when separating chips, resulting in a decrease in production efficiency. Where the distance between the two is more than 40 ⁇ m, the area of the device that does not contribute to light-emission increases, resulting in an increase in device area. This reduces the number of devices produced per unit area of a wafer.
  • the semiconductor light-emitting device of an example embodiment may further include a bonding wire connected to the front electrode. Since the front electrode is provided in opposed relation with the central region of the current-blocking layer, there is no need for providing a wire bonding area in peripheral portions of the semiconductor light-emitting device such as the outer region of the current-blocking layer, whereby the size of the device can be reduced.
  • FIG. 1 illustrates a first example embodiment.
  • a semiconductor light-emitting device 1 of the first embodiment includes an n-type GaAs substrate 3 having an n-type AuGe electrode 2 .
  • the device 1 also includes, in the order recited, a light-emitting region layer 6 serving as a light-emitting layer, a p-type AlGaInP current-spreading layer 9 and a p-type AuZn electrode 10 serving as a light-extraction side electrode (front electrode).
  • the light-emitting region layer 6 is composed of an n-type AlInP lower cladding layer 4 a , an AlGaInP active layer 5 and a p-type AlInP upper cladding layer 4 b successively formed on the substrate 3 .
  • an n-type GaP current-blocking layer 8 is partially formed on the light-emitting region layer 6 side of the layer 9 , for restricting light-emission.
  • the current-blocking layer 8 is composed of a central region 8 a and an outer region 8 b surrounding the central region 8 a via the current-spreading layer 9 .
  • a light-emitting region 7 that appears on the surface of light-extraction side of the device has an annular shape.
  • the p-type electrode 10 is disposed in opposed relation with the central region 8 a of the layer 8 , and has a bonding wire 11 connected thereto.
  • n-type GaAs substrate 3 130 ⁇ m, 3 ⁇ 10 18 cm ⁇ 3
  • n-type AlInP lower cladding layer 4 a (1 ⁇ m, Al 0.5 In 0.5 P, 5.0 ⁇ 10 17 cm ⁇ 3 );
  • AlGaInP active layer 5 (0.5 ⁇ m, (Al 0.05 Ga 0.95 ) 0.5 In 0.5 P, undoped);
  • p-type AlInP upper cladding layer 4 b (1 ⁇ m, Al 0.5 In 0.5 P, 5.0 ⁇ 10 17 cm ⁇ 3 );
  • n-type GaP current-blocking layer 8 (0.3 ⁇ m, GaP, 1.0 ⁇ 10 18 cm ⁇ 3 ); and p-type AlGaInP current-spreading layer 9 (7 ⁇ m, Al 0.01 Ga 0.98 In 0.01 P, 1.0 ⁇ 10 18 cm ⁇ 3 ).
  • Silicon and zinc are used as n-type and p-type impurities, respectively.
  • the n-type GaAs substrate 3 has outer dimensions of 280 ⁇ m ⁇ 280 ⁇ m.
  • the n-type electrode 2 is formed on the entire rear surface of the substrate 3 .
  • the p-type electrode 10 is formed circularly on the center of the p-type AlGaInP current-spreading layer 9 to have a radius of 50 ⁇ m.
  • the light-emitting region layer 6 comprising the n-type AlInP cladding layer 4 a , p-type AlGaInP active layer (light-emitting layer) 5 and p-type AlInP cladding layer 4 b , and the n-type GaP current-blocking layer 8 are formed in this order by vapor-phase epitaxy using an MOCVD apparatus. After the completion of epitaxial growth, the substrate 3 on which the multilayer film is formed is temporarily taken out from the MOCDV apparatus.
  • an annular opening for forming the above-mentioned light-emitting region 7 therein is formed in the current-blocking layer 8 by means of photolithography and etching techniques.
  • the current-blocking layer 8 is designed to be composed of the central region 8 a and the outer region 8 b surrounding the central region via the annular opening.
  • An etching solution containing sulfuric acid is used for etching.
  • a resist is removed, and the MOCVD apparatus is used on the substrate 3 having the multilayer film formed thereon to form the current-spreading layer 9 on the current-blocking layer 8 including the annular opening by vapor-phase epitaxy.
  • the circular p-type AuZn electrode 10 having a radius of 50 ⁇ m is formed on the current-spreading layer 9 .
  • the substrate 3 is processed to have a thickness of 130 ⁇ m.
  • the n-type AuGe electrode 2 is then formed on the rear surface of the substrate 3 , followed by a heat treatment, to complete the semiconductor light-emitting device. Still after this, the bonding wire 11 is connected to the electrode 10 .
  • the radius of a circle defined by the inner contour (inner perimeter or inner boundary) 7 a of the light-emitting region (annular opening) 7 is fixed to 80 ⁇ m, and the size of a circle defined by its outer contour (outer perimeter or outer opening) 7 b is changed, to form semiconductor light-emitting devices having light-emitting regions of four different widths and a semiconductor light-emitting device having a light-emitting region of different shape. More specifically, the light-emitting regions having four different widths are formed by making the difference in radius between the outer perimeters of the light-emitting region 7 and the electrode 10 be 7.1 times, 9.3 times, 10.7 times and 12.1 times the thickness of the current-spreading layer 9 .
  • FIG. 3 seen on the light-extraction side of the device is an annular light-emitting region L surrounded by a region N comprising the central and outer regions 8 a , 8 b of the non-light-emitting current-blocking layer.
  • Reference numeral 10 denotes the light-extraction side electrode which is opposed to the central region.
  • the light-emitting region having a quasi-ring-form outer perimeter (outer boundary) 7 b is formed by making the edges of a square arced.
  • the edges of the outer perimeter 7 b are chamfered such that the difference between the side length of the square (with unchamfered edges) and the radius of the outer perimeter of the electrode 10 is 7.8 times the thickness of the current-spreading layer 9 , and the difference in radius between the outer circle 7 b and the p-type electrode 10 is 10.7 times the thickness of the current-spreading layer 9 .
  • a current of 20 mA is fed to each of the semiconductor light-emitting devices having the above-mentioned five types of opening, and their luminous intensities are measured.
  • FIG. 5 seen on the light-extraction side of the device is the annular light-emitting region L surrounded by the region N comprising the central and outer regions 8 a , 8 b of the non-light-emitting current-blocking layer.
  • Reference numeral 10 denotes the light-extraction side electrode which is opposed to the central region 7 a.
  • a semiconductor light-emitting device of a conventional type shown in FIG. 8 which has no current-blocking layer in the outer region of a current-spreading layer is produced under the same conditions as above, and the luminous intensity thereof is also measured under the same conditions as above.
  • the results of the measurements are shown in FIG. 6 .
  • the horizontal axis in FIG. 6 represents a number with which the thickness of the p-type current-spreading layer is multiplied to give the width (W) of the light-emitting region.
  • the vertical axis in FIG. 6 represents a relative value of the luminous intensity of the device according to the present invention with respect to that of the conventional semiconductor light-emitting device.
  • the luminous intensity improves 1.2 times, 1.3 times, 1.25 times and 1.05 times when the difference in radius between the outer perimeters of the light-emitting region 7 and electrode 10 is 7.1 times, 9.3 times, 10.7 times and 12.1 times the thickness of the current-spreading layer 9 , respectively.
  • the luminous intensity improves 1.25 times when the device has the quasi-ring-form light-emitting region.
  • the difference is 7.1 times to 10.7 times the thickness of the current-spreading layer 9 , the current density becomes sufficiently high and the luminous intensity greatly improves over the conventional device (for example, 13% increase).
  • the quasi-ring-form light-emitting region With the quasi-ring-form light-emitting region, an improvement in luminous intensity is observed.
  • the width of the arced edges which form the quasi-ring-form is 25 ⁇ m or larger, it is found that uniform light-emission and an improvement in luminous intensity are achieved.
  • the width of the arced edges is in the range of 25 ⁇ m to 35 ⁇ m, light-emission is more uniform and luminous intensity is further improved.
  • the horizontal axis represents a ratio between the maximum value (W 2 ) and minimum value (W 1 ) of the width of the light-emitting region (annular opening), and the vertical axis represents a relative value of the luminous intensity of the device according to the present invention with respect to that of the conventional semiconductor light-emitting device.
  • the ratio between the maximum and minimum values (W 2 and W 1 ) is 1.6 and 1.8
  • the relative value of the luminous intensities is 1.05 and 1.00, respectively.
  • the ratio between the maximum and minimum values (W 2 and W 1 ) is 1.0, 1.2 and 1.4
  • the relative value of the luminous intensities are 1.24, 1.23 and 1.25, respectively.
  • a AlGaInP-based semiconductor light-emitting device is used, but as the present invention relates to the structure of a light-emitting device, the similar effects can be achieved even with the use of a GaAlAs-based or GaN-based semiconductor light-emitting device or the like.

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Led Devices (AREA)

Abstract

A semiconductor light-emitting device includes: a semiconductor substrate; a light-emitting layer formed on the semiconductor substrate; a current-blocking layer formed on a part of the light-emitting layer for restricting light-emission; a current-spreading layer formed on the current-blocking layer and the other part of the light-emitting layer; a front electrode formed on the current-spreading layer; and a rear electrode formed on a rear side of the semiconductor substrate. The current-blocking layer is composed of a central region and an outer region which surrounds the central region via a part of the current-spreading layer, so that a light-emitting region that appears on a front surface of the device has an annular shape. The front electrode and the central region of the current-blocking layer are opposed to each other.

Description

CROSS-REFERENCE TO RELATED APPLICATION
This application is related to Japanese Patent applications No. 2003-370717 filed on Oct. 30, 2003, and No. 2004-238588 filed on Aug. 18, 2004, whose priorities are claimed under 35 USC §119, the disclosures of which are incorporated by reference in their entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a semiconductor light-emitting device, and more particularly, to a semiconductor light-emitting device in which a light-emitting region provided on a surface of light-extraction side of the device has an annular shape.
2. Description of Related Art
FIGS. 8 and 9 are a plan view and sectional view of a conventional semiconductor light-emitting device, respectively. FIG. 10 is an explanatory view illustrating a light-emitting state of the conventional semiconductor light-emitting device (see, for example, Japanese Unexamined Patent Publication No. HEI 4(1992)-229665).
In FIGS. 8 to 10, a semiconductor light-emitting device 21 includes: a substrate 23 having an electrode 22 formed on its rear surface, and a lower cladding layer 24 a, an active layer 25, an upper cladding layer 24 b, a current-spreading layer 29 and an electrode 30 formed in this order on the substrate 23. The lower cladding layer 24 a, active layer 25 and upper cladding layer 24 b constitute a light-emitting region layer (light-emitting layer) 26. The light-emitting device 21 further includes, in a central region of the current-spreading layer 29, a current-blocking layer 28 formed on the light-emitting region layer 26 side of the layer 29. The current-blocking layer 28 is formed at a position where it opposes the electrode 30 located on the current-spreading layer 29.
Current injected into the current-spreading layer 29 from the electrode 30 spreads to the periphery of the current-blocking layer 28 and is then introduced into the light-emitting region layer 26, so that a light-emitting region 27 emits light. This allows for light-emission in portions other than the portion directly underneath the electrode 30. Consequently, the generated light is not cut off by the electrode 30 and thus, improving the efficiency of the device.
FIGS. 11 and 12 are a plan view and sectional view of another conventional semiconductor light-emitting device, respectively. FIG. 13 is an explanatory view illustrating a light-emitting state of the conventional light-emitting device (see, for example, Japanese Unexamined Patent Publication No. HEI 11(1999)-26810).
In FIGS. 11 to 13, a semiconductor light-emitting device 41 includes: a substrate 43 having an electrode 42 formed on its rear surface, and a lower cladding layer 44 a, an active layer 45, an upper cladding layer 44 b, a current-spreading layer 49 and an electrode 50 formed in this order on the substrate 43. The lower cladding layer 44 a, active layer 45 and upper cladding layer 44 b constitute a light-emitting region layer (light-emitting layer) 46. The light-emitting device 41 further includes, in an outer region of the current-spreading layer 49, a current-blocking layer (current-narrowing layer) 48 formed on the light-emitting region layer 46 side of the layer 49. The electrode 50 has an opening in the center thereof and is formed at a position where it opposes the current-blocking layer 48.
Current injected into the current spreading layer 49 from the electrode 50 is concentrated in the middle of the layer 49 and is then introduced into the light-emitting region layer 46, so that a light-emitting region 47 emits light. Since the current is concentrated in the middle of the device, a higher current density is obtained in the middle of the device. As the current density increases, the percentage of current that recombines without emitting light decreases and thus, improving the luminous intensity.
With the structure shown in FIGS. 8 to 10, however, currents spread freely to portions other than the current-blocking layer 28, whereby the density of current decreases.
The structure shown in FIGS. 11 to 13 requires a wire-bonding area 51 to be provided in a corner of the device. The wire-bonding area 51 usually needs a diameter of about 90 μm, and this obstructs reduction in device size.
BRIEF SUMMARY
The present invention provides a semiconductor light-emitting device in which the density of current introduced into the light-emitting layer is increased to improve the luminous intensity and to achieve uniform light-emission, and in which wire-bonding area is not required and hence, miniaturization of the device is possible.
A semiconductor light-emitting device comprises: a semiconductor substrate; a light-emitting layer formed on the semiconductor substrate; a current-blocking layer formed on a part of the light-emitting layer for restricting light-emission; a current-spreading layer formed on the current-blocking layer and the other part of the light-emitting layer; a front electrode formed on the current-spreading layer; and a rear electrode formed on a rear side of the semiconductor substrate, wherein the current-blocking layer is composed of a central region and an outer region which surrounds the central region via a part of the current-spreading layer, so that a light-emitting region that appears on a front surface of the device has an annular shape, and the front electrode and the central region of the current-blocking layer are opposed to each other.
In accordance with an example embodiment, the current-blocking layer comprises the central and outer regions, so that the light-emitting region that appears on the front surface of the device is defined between the central and outer regions to have an annular shape. This allows for improved luminous intensity over devices that do not include the outer region of the current-blocking layer, and for uniform light-emission.
By disposing the front electrode in opposed relation with the central region of the current-blocking layer, there is no need to provide a wire-bonding area in the outer region of the current-blocking layer and thus, the semiconductor light-emitting device can be miniaturized.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view illustrating the general construction of a semiconductor light-emitting device according to a first example embodiment;
FIG. 2 is a sectional view of the device of FIG. 1;
FIG. 3 is an explanatory view illustrating a light-emitting state of the top of the device of FIG. 1;
FIG. 4 is a plan view illustrating the general construction of a semiconductor light-emitting device according to another example embodiment;
FIG. 5 is an explanatory view illustrating a light-emitting state of the top of the device of FIG. 4;
FIG. 6 is a graph illustrating a relationship between the width of a light-emitting region (annular opening) of the device according to the present invention and the ratio of the luminous intensity of the device according to the first embodiment to that of a conventional light-emitting device;
FIG. 7 is a graph illustrating a relationship between the ratio of maximum to minimum values of the width of a light-emitting region (annular opening) of the device according to the present invention and the ratio of the luminous intensity of the device according to the second embodiment to that of the conventional semiconductor light-emitting device;
FIG. 8 is a plan view illustrating the general construction of a conventional semiconductor light-emitting device;
FIG. 9 is a sectional view of the device of FIG. 8.
FIG. 10 is an explanatory view illustrating a light-emitting state of the top of the device of FIG. 8;
FIG. 11 is a plan view illustrating the general construction of another conventional semiconductor light-emitting device;
FIG. 12 is a sectional view of the device of FIG. 11; and
FIG. 13 is an explanatory view illustrating a light-emitting state of the top of the device of FIG. 11.
 DESCRIPTION OF THE PREFERRED EMBODIMENTS
A semiconductor light-emitting device according to example embodiment comprises: a semiconductor substrate; a light-emitting layer formed on the semiconductor substrate; a current-blocking layer formed on a part of the light-emitting layer for restricting light-emission; a current-spreading layer formed on the current-blocking layer and the other part of the light-emitting layer; a front electrode formed on the current-spreading layer; and a rear electrode formed on a rear side of the semiconductor substrate.
According to the present invention, the semiconductor substrate may be any as long as the light-emitting layer (hereinafter also referred to as a light-emitting region layer) can be formed thereon. The substrate preferably lattice-matches the light-emitting layer. Examples of the substrate include substrates of compound semiconductors such as GaAs, GaN, GaP, InP, ZnO and ZnSe, and of elementary semicondutors such as Si and Ge. The substrate may have n- or p-type conductivity.
The rear electrode (may be referred to as a substrate-side electrode) may be formed of a conductive material, and preferably has an ohmic contact with the substrate. The rear electrode may be formed of, for example, a metal such as Au, Pt, Al, Ni or Ti, or an alloy such as AlGe or AlZn. For example, where the substrate is of n-type semiconductor, an AlGe electrode is preferably used.
The rear electrode may be formed by, for example, forming a metal or alloy film by means of vapor deposition, sputtering or the like, followed by a heat treatment of the film. The rear electrode may be formed on a side or rear surface of the substrate.
Between the rear electrode and the substrate, a contact layer, for example, may be provided for obtaining an ohmic contact.
The light-emitting layer formed on the substrate may be any as long as it emits light by passing a current thereto. The light-emitting layer preferably has a double heterojunction structure of a lower cladding layer, active layer and upper cladding layer, but may have a single heterojunction structure or homojunction structure.
Semiconductor layers that constitute the light-emitting layer may be formed of, for example, a compound semiconductor. Examples of the compound semiconductor include a binary compound semiconductor such as GaAs, GaP or GaN, a ternary compound semiconductor such as AlInP, AlGaAs, GaAsP, InGaAs or InGaN, and a quaternary compound semiconductor such as InGaAsP or AlGaInP. The composition of the compound semiconductor may be determined so as to obtain light of a desirable wavelength.
Where the light-emitting layer has the double heterojunction structure, for example, the composition of the compound semiconductor used for the active layer is determined so as to obtain light of a desirable wavelength. The compositions of the lower and upper cladding layers are determined so that the band gaps thereof are greater than that of the active layer.
The light-emitting layer of any of the double heterojunction, single heterojunction or homojunction structure comprises two or more semiconductor layers. The lowermost layer of the semiconductor layers has the same conductivity type as the substrate, and the uppermost layer of the semiconductor layers has a different conductivity type from the substrate. The active layer of the double heterojunction structure may be undoped or doped with n-type or p-type impurities.
Each semiconductor layer that constitutes the light-emitting layer may be formed by a method such as LPE, MOCVD, MBE or MOMBE. The semiconductor layer of n-type may be formed by doping Si, S, Se, Te or the like, and the semiconductor layer of p-type may be formed by doping Zn, Mg, C, Be or the like.
Other semiconductor layers such as the contact layer, a buffer layer, a cap layer, the current-blocking layer and the current-spreading layer which will be described later may be formed by similar methods.
Between the rear electrode and the light-emitting layer, the buffer layer, for example, may be provided for offsetting the difference in lattice constant.
The current-blocking layer is formed on a part of the light-emitting layer for restricting light-emission, and the current-spreading layer is formed on the current-blocking layer and the other part of the light-emitting layer. The current-blocking layer may be any as long as it prevents, or makes difficult, the flowing of currents from the current-spreading layer to the light-emitting layer. The current-blocking layer may be formed of, for example, a semiconductor which is doped with impurities of different conductivity type from the uppermost layer of the light-emitting layer or which has a small carrier concentration. Examples of such a semiconductor include GaP, AlGaP, AlGaAs and AlGaInP.
The current-blocking layer may also be formed of a semiconductor which has the same conductivity type as the uppermost layer of the light-emitting layer and which allows a heterobarrier formed between the current-blocking layer and the uppermost layer of the light-emitting layer to be greater than that formed between the current-spreading layer and the uppermost layer. For example, the uppermost layer of the light-emitting layer, current-blocking layer and current-spreading layer may be formed of p-type AlGaInP, p-type GaAs and p-type GaAlAs, respectively.
The current-spreading layer may be any as long as it spreads current fed from the front electrode. The current-spreading layer is preferably formed of a material having a band gap greater than the energy of light generated in the light-emitting layer so that the light generated in the light-emitting layer is less absorbed. Further, the current-spreading layer is preferably formed of a material having a small resistivity so as to facilitate the current spreading.
The current-spreading layer may be formed of, for example, a compound semiconductor. Examples of the compound semiconductor include a binary compound semiconductor such as GaP, a ternary compound semiconductor such as GaAlAs or InGaN, and a quaternary compound semiconductor such as AlGaInP or AlGaInN. The current-spreading layer preferably has the same conductivity type as the uppermost layer of the light-emitting layer.
According to an example embodiment, the current-blocking layer is composed of a central region and an outer region surrounding the central region via a part of the current-spreading layer, so that a light-emitting region that appears on a front surface of the semiconductor light-emitting device has a circular shape.
Normally, the current-blocking layer is formed on the light-emitting layer prior to the formation of the current-spreading layer. The current-blocking layer is formed such that an annular opening is formed between its central and outer regions. The annular opening may be formed by partially removing the current-blocking layer that is formed on the entire surface of the light-emitting layer by means of photolithography and etching. The term “annular” used herein includes a circular shape, a polygonal shape, and a ring- or loop-shape obtained from a rounded polygon. The “opening” is preferably a through hole, but may be a blind hole. Where the “opening” is a blind hole, a semiconductor which forms the current-spreading layer is filled in the annular opening, that is, between the central and outer regions.
Instead of forming the annular opening in the current-blocking layer as described above, an annular current-flow-through region may be formed. For example, a semiconductor doped with impurities of different conductivity type from the uppermost layer of the light-emitting layer or a semiconductor having a small carrier concentration, such as GaP, AlGaAs or AlGaInp may be used to form the current-blocking layer. Then, impurities of the same conductivity type as the uppermost layer may be annularly diffused to form the annular current-flow-through region.
Alternatively, a semiconductor layer in which current can easily flow may be formed. Then, the layer may be doped with impurities of different conductivity type from the uppermost layer except for a portion to serve as the annular current-flow-through region.
Between the current-blocking layer and the light-emitting layer, the cap layer may be formed. Where the uppermost layer of the light-emitting layer is formed of an easily oxidizable material, for example, the cap layer may be formed of an oxidation-resistant material. The cap layer may be formed of, for example, a material that does not contain aluminum, such as GaInP. The cap layer may also be formed of a material having a small aluminum content.
According to an example embodiment, the central region of the current-blocking layer and the front electrode (may also be referred to as a light-extraction side electrode) are opposed to each other.
The front electrode may be formed of a conductive material, and is preferably capable of forming an ohmic contact with the current-spreading layer. The front electrode may be formed of, for example, a metal such as Au, Pt, Al, Ni or Ti, or an alloy such as AlGe or AlZn. Where the substrate is of p-type semiconductor, an AlZn electrode is preferably used.
The front electrode may be formed by, for example, forming a metal or alloy film by means of vapor deposition, sputtering or the like, and then processing the film into a desirable shape by photolithography and etching techniques, followed by heat treatment.
The front electrode may have any shape and size, and preferably has such shape and size that a wire-bonding area can be provided thereon. The front electrode preferably has a circular shape, and a radius of 45 μm or greater so that a space for wire bonding is secured. In order to provide enough space therefor, it is more preferable that the front electrode has a radius of 50 μm or greater.
Between the substrate and the front electrode, the contact layer formed of, for example, GaAs may be provided for obtaining an ohmic contact.
According to an example embodiment, as described above, the current-blocking layer is composed of the central region and the outer region surrounding the central region via a part of the current-spreading layer so that a light-emitting region that appears on the front surface of the light-emitting device has an annular shape. Here, the outer contour (outer perimeter) of the front electrode is preferably set to have a size substantially equal to that of the inner contour (inner perimeter) of the light-emitting region or a size such that the outer contour of the front electrode falls within the inner contour of the light-emitting region (i.e., the outer contour of the front electrode is smaller than the inner contour of the light-emitting region). This is because, when the front electrode is larger than the inner contour of the light-emitting region, the light-emitting layer emits light under the front electrode, and the emitted light is shielded by the front electrode, preventing the light from being taken outside.
The outer contour of the front electrode is preferably set such that the width between the outer contour of the front electrode and the inner contour of the light-emitting region is substantially uniform. By doing so, driving current is uniformly fed into the light-emitting layer.
In terms of formability, the light-emitting region preferably has a circularly annular shape and the front electrode preferably has a circular shape. The difference in radius between the outer perimeters of the light-emitting region and the front electrode is preferably 7.1 to 10.7 times the thickness of the current-spreading layer. Further, it is preferable that the distance between the inner and outer perimeters of the light-emitting region, that is, the width of the light-emitting region is 25 μm or greater. The ratio of the maximum to minimum values of this distance is preferably 1.4 times or smaller.
The radius of the inner perimeter of the circularly annular light-emitting region is preferably 1.3 to 1.7 times the radius of the outer perimeter of the front electrode. Where the ratio is less than 1.3, a highly-developed alignment technique is required at the formation of the front electrode, and thereby the production efficiency of the device decreases. Where the ratio is more than 1.7 times, the area of the device that does not contribute to light-emission increases, resulting in an increase in device area. This reduces the number of devices produced per unit area of a wafer.
Preferably, the width of the annular light-emitting region is substantially uniform. By doing so, driving current is uniformly fed into the light-emitting layer.
The width of the annular light-emitting region is preferably 25 μm or greater as described above, and more preferably from 25 μm to 40 μm inclusive. Where the width is smaller than 25 μm, there is a fear that etching irregularities may be caused, which leads to a malfunction of the device. Where the width is larger than 40 μm, there is a fear that luminous intensity may decrease due to variations in current density in the light-emitting region.
The outer contour (outer boundary or outer perimeter) of the light-emitting region (annular opening ) is preferably 20 μm or more apart from the outer contour of the semiconductor substrate, and more preferably, from 15 μm or more to 40 μm or less apart from the outer contour of the substrate. Where the distance between the two is less than 15 μm, there is a higher possibility of cutting the annular opening when separating chips, resulting in a decrease in production efficiency. Where the distance between the two is more than 40 μm, the area of the device that does not contribute to light-emission increases, resulting in an increase in device area. This reduces the number of devices produced per unit area of a wafer.
The semiconductor light-emitting device of an example embodiment may further include a bonding wire connected to the front electrode. Since the front electrode is provided in opposed relation with the central region of the current-blocking layer, there is no need for providing a wire bonding area in peripheral portions of the semiconductor light-emitting device such as the outer region of the current-blocking layer, whereby the size of the device can be reduced.
With reference to the attached drawings, example embodiments will hereinafter be described by way of embodiments thereof. It should be understood that the present invention be not limited to these embodiments.
First Embodiment
FIG. 1 illustrates a first example embodiment. A semiconductor light-emitting device 1 of the first embodiment includes an n-type GaAs substrate 3 having an n-type AuGe electrode 2. The device 1 also includes, in the order recited, a light-emitting region layer 6 serving as a light-emitting layer, a p-type AlGaInP current-spreading layer 9 and a p-type AuZn electrode 10 serving as a light-extraction side electrode (front electrode). The light-emitting region layer 6 is composed of an n-type AlInP lower cladding layer 4 a, an AlGaInP active layer 5 and a p-type AlInP upper cladding layer 4 b successively formed on the substrate 3. Inside the current-spreading layer 9, an n-type GaP current-blocking layer 8 is partially formed on the light-emitting region layer 6 side of the layer 9, for restricting light-emission. The current-blocking layer 8 is composed of a central region 8 a and an outer region 8 b surrounding the central region 8 a via the current-spreading layer 9. A light-emitting region 7 that appears on the surface of light-extraction side of the device has an annular shape.
The p-type electrode 10 is disposed in opposed relation with the central region 8 a of the layer 8, and has a bonding wire 11 connected thereto.
The thickness, composition and carrier concentration of each layer are set as follows: n-type GaAs substrate 3 (130 μm, 3×1018 cm−3); n-type AlInP lower cladding layer 4 a (1 μm, Al0.5In0.5P, 5.0×1017 cm−3); AlGaInP active layer 5 (0.5 μm, (Al0.05Ga0.95)0.5In0.5P, undoped); p-type AlInP upper cladding layer 4 b (1 μm, Al0.5In0.5P, 5.0×1017 cm−3); n-type GaP current-blocking layer 8 (0.3 μm, GaP, 1.0×1018 cm−3); and p-type AlGaInP current-spreading layer 9 (7 μm, Al0.01Ga0.98In0.01P, 1.0×1018 cm−3). Silicon and zinc are used as n-type and p-type impurities, respectively.
The n-type GaAs substrate 3 has outer dimensions of 280 μm×280 μm. The n-type electrode 2 is formed on the entire rear surface of the substrate 3. The p-type electrode 10 is formed circularly on the center of the p-type AlGaInP current-spreading layer 9 to have a radius of 50 μm.
Next, with reference to FIG. 1, an explanation will be given on a manufacturing method of the semiconductor light-emitting device of the first embodiment. The thickness, composition and carrier concentration of each layer are as described above.
On the n-type GaAs substrate 3, the light-emitting region layer 6 comprising the n-type AlInP cladding layer 4 a, p-type AlGaInP active layer (light-emitting layer) 5 and p-type AlInP cladding layer 4 b, and the n-type GaP current-blocking layer 8 are formed in this order by vapor-phase epitaxy using an MOCVD apparatus. After the completion of epitaxial growth, the substrate 3 on which the multilayer film is formed is temporarily taken out from the MOCDV apparatus.
Next, an annular opening for forming the above-mentioned light-emitting region 7 therein is formed in the current-blocking layer 8 by means of photolithography and etching techniques. In other words, the current-blocking layer 8 is designed to be composed of the central region 8 a and the outer region 8 b surrounding the central region via the annular opening. An etching solution containing sulfuric acid is used for etching. Then, a resist is removed, and the MOCVD apparatus is used on the substrate 3 having the multilayer film formed thereon to form the current-spreading layer 9 on the current-blocking layer 8 including the annular opening by vapor-phase epitaxy.
Subsequently, the circular p-type AuZn electrode 10 having a radius of 50 μm is formed on the current-spreading layer 9. Then, the substrate 3 is processed to have a thickness of 130 μm. The n-type AuGe electrode 2 is then formed on the rear surface of the substrate 3, followed by a heat treatment, to complete the semiconductor light-emitting device. Still after this, the bonding wire 11 is connected to the electrode 10.
Hereinafter, examined are variations in luminous intensity when the difference in radius between the outer perimeters of the light-emitting region and the electrode 10 is changed. The difference in radius is changed such that it becomes multiples of the thickness of the current-spreading layer 9.
The radius of a circle defined by the inner contour (inner perimeter or inner boundary) 7 a of the light-emitting region (annular opening) 7 is fixed to 80 μm, and the size of a circle defined by its outer contour (outer perimeter or outer opening) 7 b is changed, to form semiconductor light-emitting devices having light-emitting regions of four different widths and a semiconductor light-emitting device having a light-emitting region of different shape. More specifically, the light-emitting regions having four different widths are formed by making the difference in radius between the outer perimeters of the light-emitting region 7 and the electrode 10 be 7.1 times, 9.3 times, 10.7 times and 12.1 times the thickness of the current-spreading layer 9.
Thus, as shown in FIG. 3, seen on the light-extraction side of the device is an annular light-emitting region L surrounded by a region N comprising the central and outer regions 8 a, 8 b of the non-light-emitting current-blocking layer. Reference numeral 10 denotes the light-extraction side electrode which is opposed to the central region.
Further, as shown in FIG. 4, the light-emitting region having a quasi-ring-form outer perimeter (outer boundary) 7 b is formed by making the edges of a square arced. The edges of the outer perimeter 7 b are chamfered such that the difference between the side length of the square (with unchamfered edges) and the radius of the outer perimeter of the electrode 10 is 7.8 times the thickness of the current-spreading layer 9, and the difference in radius between the outer circle 7 b and the p-type electrode 10 is 10.7 times the thickness of the current-spreading layer 9.
A current of 20 mA is fed to each of the semiconductor light-emitting devices having the above-mentioned five types of opening, and their luminous intensities are measured. As shown in FIG. 5, seen on the light-extraction side of the device is the annular light-emitting region L surrounded by the region N comprising the central and outer regions 8 a, 8 b of the non-light-emitting current-blocking layer. Reference numeral 10 denotes the light-extraction side electrode which is opposed to the central region 7 a.
A semiconductor light-emitting device of a conventional type shown in FIG. 8, which has no current-blocking layer in the outer region of a current-spreading layer is produced under the same conditions as above, and the luminous intensity thereof is also measured under the same conditions as above.
The results of the measurements are shown in FIG. 6. The horizontal axis in FIG. 6 represents a number with which the thickness of the p-type current-spreading layer is multiplied to give the width (W) of the light-emitting region. The vertical axis in FIG. 6 represents a relative value of the luminous intensity of the device according to the present invention with respect to that of the conventional semiconductor light-emitting device. The luminous intensity improves 1.2 times, 1.3 times, 1.25 times and 1.05 times when the difference in radius between the outer perimeters of the light-emitting region 7 and electrode 10 is 7.1 times, 9.3 times, 10.7 times and 12.1 times the thickness of the current-spreading layer 9, respectively. Further, the luminous intensity improves 1.25 times when the device has the quasi-ring-form light-emitting region. As a result, it is found that, when the difference is 7.1 times to 10.7 times the thickness of the current-spreading layer 9, the current density becomes sufficiently high and the luminous intensity greatly improves over the conventional device (for example, 13% increase).
With the quasi-ring-form light-emitting region, an improvement in luminous intensity is observed. When the width of the arced edges which form the quasi-ring-form is 25 μm or larger, it is found that uniform light-emission and an improvement in luminous intensity are achieved. When the width of the arced edges is in the range of 25 μm to 35 μm, light-emission is more uniform and luminous intensity is further improved.
Further, in FIG. 7, the horizontal axis represents a ratio between the maximum value (W2) and minimum value (W1) of the width of the light-emitting region (annular opening), and the vertical axis represents a relative value of the luminous intensity of the device according to the present invention with respect to that of the conventional semiconductor light-emitting device. When the ratio between the maximum and minimum values (W2 and W1) is 1.6 and 1.8, the relative value of the luminous intensities is 1.05 and 1.00, respectively. When the ratio between the maximum and minimum values (W2 and W1) is 1.0, 1.2 and 1.4, the relative value of the luminous intensities are 1.24, 1.23 and 1.25, respectively. As a result, when the width of the arced edges which form the quasi-ring-form (the distance between the inner and outer perimeters of the edge of the light-emitting region) is 25 μm or larger and the ratio between the maximum and minimum values of the width is 1.4 times or lower, a 1.2 times improvement in luminous intensity is observed.
In this embodiment, a AlGaInP-based semiconductor light-emitting device is used, but as the present invention relates to the structure of a light-emitting device, the similar effects can be achieved even with the use of a GaAlAs-based or GaN-based semiconductor light-emitting device or the like.

Claims (8)

1. A semiconductor light-emitting device comprising:
a semiconductor substrate;
a light-emitting layer formed on the semiconductor substrate;
a current-blocking layer formed on a part of the light-emitting layer for restricting light-emission;
a current-spreading layer formed on the current-blocking layer and the other part of the light-emitting layer;
a front electrode formed on the current-spreading layer;
a rear electrode formed on a rear side of the semiconductor substrate,
wherein the current-blocking layer is composed of a central region and an outer region which surrounds the central region via a part of the current-spreading layer, so that a light-emitting region that appears on a front surface of the device has an annular shape;
wherein the front electrode and the central region of the current-blocking layer are opposed to each other,
wherein the light-emitting region has a circularly annular shape, and the front electrode has a circular shape; and
wherein a difference in radius between outer perimeters of the circularly annular light-emitting region and the circular front electrode is 7.1 to 10.7 times the thickness of the current-spreading layer.
2. A semiconductor light-emitting device as set forth in claim 1, further comprising a bonding wire connected to the front electrode.
3. A semiconductor light-emitting device as set forth in claim 1, wherein the radius of the inner perimeter of the circularly annular light-emitting region is 1.3 to 1.7 times the radius of the outer perimeter of the circular front electrode.
4. A semiconductor light-emitting device as set forth in claim 1, wherein the light-emitting region has a quasi-ring-form outer perimeter formed as a square with arced edges.
5. A semiconductor light-emitting device comprising:
a semiconductor substrate;
a light-emitting layer formed on the semiconductor substrate;
a current-blocking layer formed on a part of the light-emitting layer for restricting light-emission;
a current-spreading layer formed on the current-blocking layer and the other part of the light-emitting layer;
a front electrode formed on the current-spreading layer;
a rear electrode formed on a rear side of the semiconductor substrate,
wherein the current-blocking layer is composed of a central region and an outer region which surrounds the central region via a part of the current-spreading layer, so that a light-emitting region that appears on a front surface of the device has an annular shape;
wherein the front electrode and the central region of the current-blocking layer are opposed to each other;
wherein the front electrode has an outer contour that is substantially evenly spaced from an inner contour of the light-emitting region;
wherein the light-emitting region has a circularly annular shape, and the front electrode has a circular shape; and
wherein the radius of the inner perimeter of the circularly annular light emitting region is 1.3 to 1.7 times the radius of the outer perimeter of the circular front electrode.
6. A semiconductor light-emitting device comprising:
a semiconductor substrate;
a light-emitting layer formed on the semiconductor substrate;
a current-blocking layer formed on a part of the light-emitting layer for restricting light-emission;
a current-spreading layer formed on the current-blocking layer and the other part of the light-emitting layer;
a front electrode formed on the current-spreading layer;
a rear electrode formed on a rear side of the semiconductor substrate,
wherein the current-blocking layer is composed of a central region and an outer region which surrounds the central region via a part of the current-spreading layer, so that a light-emitting region that appears on a front surface of the device has an annular shape; wherein the front electrode and the central region of the current-blocking layer are opposed to each other, wherein the distance between the inner and outer contours of the annular light-emitting region is 25 μm or greater, and the ratio of the maximum to minimum values of said distance is set to 1.4 times or lower.
7. A semiconductor light-emitting device comprising:
a semiconductor substrate;
a light-emitting layer formed on the semiconductor substrate;
a current-blocking layer formed on a part of the light-emitting layer for restricting light-emission;
a current-spreading layer formed on the current-blocking layer and the other part of the light-emitting layer;
a front electrode formed on the current-spreading layer;
a rear electrode formed on a rear side of the semiconductor substrate,
wherein the current-blocking layer is composed of a central region and an outer region which surrounds the central region via a part of the current-spreading layer, so that a light-emitting region that appears on a front surface of the device has an annular shape;
wherein the front electrode and the central region of the current-blocking layer are opposed to each other,
wherein the annular light-emitting region has an outer contour that is 15 μm or more apart from an outer contour of the semiconductor light-emitting device.
8. A semiconductor light-emitting device comprising:
a semiconductor substrate;
a light-emitting layer formed on the semiconductor substrate;
a current-blocking layer formed on a part of the light-emitting layer for restricting light-emission;
a current-spreading layer formed on the current-blocking layer and the other part of the light-emitting layer;
a front electrode formed on the current-spreading layer;
a rear electrode formed on a rear side of the semiconductor substrate,
wherein the current-blocking layer is composed of a central region and an outer region which surrounds the central region via a part of the current-spreading layer, so that a light-emitting region that appears on a front surface of the device has an annular shape;
wherein the front electrode and the central region of the current-blocking layer are opposed to each other;
wherein the front electrode has an outer contour that is substantially equal in shape and size to an inner contour of the annular light-emitting region, or has an outer contour that falls within the inner contour of the light-emitting region;
wherein a distance between the inner and outer contours of the annular light-emitting region is 25 μm or greater, and a ratio of the maximum to minimum values of said distance is set to 1.4 times or lower.
US10/969,015 2003-10-30 2004-10-21 Semiconductor light-emitting device having annular shape light emitting region and current blocking layer Active 2025-04-14 US7247985B2 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP2003370717 2003-10-30
JP2003-370717 2003-10-30
JP2004-238588 2004-08-18
JP2004238588A JP2005159299A (en) 2003-10-30 2004-08-18 Semiconductor light emitting element

Publications (2)

Publication Number Publication Date
US20050093428A1 US20050093428A1 (en) 2005-05-05
US7247985B2 true US7247985B2 (en) 2007-07-24

Family

ID=34554751

Family Applications (1)

Application Number Title Priority Date Filing Date
US10/969,015 Active 2025-04-14 US7247985B2 (en) 2003-10-30 2004-10-21 Semiconductor light-emitting device having annular shape light emitting region and current blocking layer

Country Status (4)

Country Link
US (1) US7247985B2 (en)
JP (1) JP2005159299A (en)
CN (1) CN100376042C (en)
TW (1) TWI302383B (en)

Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070187702A1 (en) * 2006-02-16 2007-08-16 Samsung Electro-Mechanics Co., Ltd. Facet extraction LED and method for manufacturing the same
US8395165B2 (en) 2011-07-08 2013-03-12 Bridelux, Inc. Laterally contacted blue LED with superlattice current spreading layer
US20130264539A1 (en) * 2008-08-18 2013-10-10 Semiconductor Manufacturing Company Ltd. Light-Emitting Diode with Current-Spreading Region
US8564010B2 (en) 2011-08-04 2013-10-22 Toshiba Techno Center Inc. Distributed current blocking structures for light emitting diodes
US8624278B2 (en) 2008-04-30 2014-01-07 Lg Innotek Co., Ltd. Light emitting device with current blocking layer
US8664679B2 (en) 2011-09-29 2014-03-04 Toshiba Techno Center Inc. Light emitting devices having light coupling layers with recessed electrodes
US8686430B2 (en) 2011-09-07 2014-04-01 Toshiba Techno Center Inc. Buffer layer for GaN-on-Si LED
US8698163B2 (en) 2011-09-29 2014-04-15 Toshiba Techno Center Inc. P-type doping layers for use with light emitting devices
US8853668B2 (en) 2011-09-29 2014-10-07 Kabushiki Kaisha Toshiba Light emitting regions for use with light emitting devices
US8865565B2 (en) 2011-08-02 2014-10-21 Kabushiki Kaisha Toshiba LED having a low defect N-type layer that has grown on a silicon substrate
US8916906B2 (en) 2011-07-29 2014-12-23 Kabushiki Kaisha Toshiba Boron-containing buffer layer for growing gallium nitride on silicon
US9012939B2 (en) 2011-08-02 2015-04-21 Kabushiki Kaisha Toshiba N-type gallium-nitride layer having multiple conductive intervening layers
US9012921B2 (en) 2011-09-29 2015-04-21 Kabushiki Kaisha Toshiba Light emitting devices having light coupling layers
US9130068B2 (en) 2011-09-29 2015-09-08 Manutius Ip, Inc. Light emitting devices having dislocation density maintaining buffer layers
US9142743B2 (en) 2011-08-02 2015-09-22 Kabushiki Kaisha Toshiba High temperature gold-free wafer bonding for light emitting diodes
US9159869B2 (en) 2011-08-03 2015-10-13 Kabushiki Kaisha Toshiba LED on silicon substrate using zinc-sulfide as buffer layer
US9178114B2 (en) 2011-09-29 2015-11-03 Manutius Ip, Inc. P-type doping layers for use with light emitting devices
US9343641B2 (en) 2011-08-02 2016-05-17 Manutius Ip, Inc. Non-reactive barrier metal for eutectic bonding process
US20160233399A1 (en) * 2013-11-07 2016-08-11 Toshiba Hokuto Electronics Corporation Light emitting device
US9617656B2 (en) 2011-07-25 2017-04-11 Toshiba Corporation Nucleation of aluminum nitride on a silicon substrate using an ammonia preflow

Families Citing this family (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007103725A (en) * 2005-10-05 2007-04-19 Toshiba Corp Semiconductor light emitting device
CN100438110C (en) * 2006-12-29 2008-11-26 北京太时芯光科技有限公司 LED with the current transfer penetration-enhanced window layer structure
DE102007003282B4 (en) * 2007-01-23 2023-12-21 OSRAM Opto Semiconductors Gesellschaft mit beschränkter Haftung LED chip
TWI473292B (en) * 2008-12-15 2015-02-11 Lextar Electronics Corp Light emitting diode
US8507940B2 (en) 2010-04-05 2013-08-13 Taiwan Semiconductor Manufacturing Company, Ltd. Heat dissipation by through silicon plugs
WO2013068878A1 (en) 2011-11-07 2013-05-16 Koninklijke Philips Electronics N.V. Improved p-contact with more uniform injection and lower optical loss
JP2012044232A (en) * 2011-12-02 2012-03-01 Toshiba Corp Semiconductor light emitting device
US20130221320A1 (en) * 2012-02-27 2013-08-29 Tsmc Solid State Lighting Ltd. Led with embedded doped current blocking layer
US9312432B2 (en) 2012-03-13 2016-04-12 Tsmc Solid State Lighting Ltd. Growing an improved P-GaN layer of an LED through pressure ramping
CN112151646B (en) * 2019-06-28 2021-12-21 隆达电子股份有限公司 Light emitting element
CN116978999B (en) * 2023-09-22 2024-01-02 南昌凯捷半导体科技有限公司 Current-limited Micro-LED chip and manufacturing method thereof

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04229665A (en) 1990-08-20 1992-08-19 Toshiba Corp Semiconductor light-emitting device
JPH08167738A (en) 1994-12-14 1996-06-25 Sanken Electric Co Ltd Semiconductor light emitting element
JPH1126810A (en) 1997-07-02 1999-01-29 Sharp Corp Semiconductor light emitting device
US6121635A (en) * 1997-04-15 2000-09-19 Kabushiki Kaisha Toshiba Semiconductor light-emitting element having transparent electrode and current blocking layer, and semiconductor light-emitting including the same
US20020020842A1 (en) * 2000-04-21 2002-02-21 Kazuaki Sasaki Semiconductor light-emitting device and method for manufacturing thereof
US20030001162A1 (en) * 2001-06-29 2003-01-02 Showa Denko K.K. Boron phosphide-based semiconductor device and production method thereof

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3807638B2 (en) * 1997-01-29 2006-08-09 シャープ株式会社 Semiconductor light emitting device and manufacturing method thereof
SE9700931D0 (en) * 1997-03-14 1997-03-14 Ericsson Telefon Ab L M Buried heterostructure laser

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04229665A (en) 1990-08-20 1992-08-19 Toshiba Corp Semiconductor light-emitting device
JPH08167738A (en) 1994-12-14 1996-06-25 Sanken Electric Co Ltd Semiconductor light emitting element
US6121635A (en) * 1997-04-15 2000-09-19 Kabushiki Kaisha Toshiba Semiconductor light-emitting element having transparent electrode and current blocking layer, and semiconductor light-emitting including the same
JPH1126810A (en) 1997-07-02 1999-01-29 Sharp Corp Semiconductor light emitting device
US20020020842A1 (en) * 2000-04-21 2002-02-21 Kazuaki Sasaki Semiconductor light-emitting device and method for manufacturing thereof
US20030001162A1 (en) * 2001-06-29 2003-01-02 Showa Denko K.K. Boron phosphide-based semiconductor device and production method thereof

Cited By (30)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7683385B2 (en) * 2006-02-16 2010-03-23 Samsung Electro-Mechanics Co., Ltd. Facet extraction LED and method for manufacturing the same
US20100210051A1 (en) * 2006-02-16 2010-08-19 Samsung Electro-Mechanics Co., Ltd. Facet extraction led and method for manufacturing the same
US7998767B2 (en) * 2006-02-16 2011-08-16 Samsung Led Co., Ltd. Method for manufacturing a facet extraction LED
US20070187702A1 (en) * 2006-02-16 2007-08-16 Samsung Electro-Mechanics Co., Ltd. Facet extraction LED and method for manufacturing the same
US8624278B2 (en) 2008-04-30 2014-01-07 Lg Innotek Co., Ltd. Light emitting device with current blocking layer
US8823049B2 (en) * 2008-08-18 2014-09-02 Tsmc Solid State Lighting Ltd. Light-emitting diode with current-spreading region
US20130264539A1 (en) * 2008-08-18 2013-10-10 Semiconductor Manufacturing Company Ltd. Light-Emitting Diode with Current-Spreading Region
US20150053918A1 (en) * 2008-08-18 2015-02-26 Tsmc Solid State Lighting Ltd. Light-emitting diode with current-spreading region
US8395165B2 (en) 2011-07-08 2013-03-12 Bridelux, Inc. Laterally contacted blue LED with superlattice current spreading layer
US10174439B2 (en) 2011-07-25 2019-01-08 Samsung Electronics Co., Ltd. Nucleation of aluminum nitride on a silicon substrate using an ammonia preflow
US9617656B2 (en) 2011-07-25 2017-04-11 Toshiba Corporation Nucleation of aluminum nitride on a silicon substrate using an ammonia preflow
US8916906B2 (en) 2011-07-29 2014-12-23 Kabushiki Kaisha Toshiba Boron-containing buffer layer for growing gallium nitride on silicon
US9142743B2 (en) 2011-08-02 2015-09-22 Kabushiki Kaisha Toshiba High temperature gold-free wafer bonding for light emitting diodes
US9343641B2 (en) 2011-08-02 2016-05-17 Manutius Ip, Inc. Non-reactive barrier metal for eutectic bonding process
US9012939B2 (en) 2011-08-02 2015-04-21 Kabushiki Kaisha Toshiba N-type gallium-nitride layer having multiple conductive intervening layers
US8865565B2 (en) 2011-08-02 2014-10-21 Kabushiki Kaisha Toshiba LED having a low defect N-type layer that has grown on a silicon substrate
US9159869B2 (en) 2011-08-03 2015-10-13 Kabushiki Kaisha Toshiba LED on silicon substrate using zinc-sulfide as buffer layer
US8564010B2 (en) 2011-08-04 2013-10-22 Toshiba Techno Center Inc. Distributed current blocking structures for light emitting diodes
US9070833B2 (en) 2011-08-04 2015-06-30 Kabushiki Kaisha Toshiba Distributed current blocking structures for light emitting diodes
US8686430B2 (en) 2011-09-07 2014-04-01 Toshiba Techno Center Inc. Buffer layer for GaN-on-Si LED
US8698163B2 (en) 2011-09-29 2014-04-15 Toshiba Techno Center Inc. P-type doping layers for use with light emitting devices
US9130068B2 (en) 2011-09-29 2015-09-08 Manutius Ip, Inc. Light emitting devices having dislocation density maintaining buffer layers
US9012921B2 (en) 2011-09-29 2015-04-21 Kabushiki Kaisha Toshiba Light emitting devices having light coupling layers
US9299881B2 (en) 2011-09-29 2016-03-29 Kabishiki Kaisha Toshiba Light emitting devices having light coupling layers
US9178114B2 (en) 2011-09-29 2015-11-03 Manutius Ip, Inc. P-type doping layers for use with light emitting devices
US9490392B2 (en) 2011-09-29 2016-11-08 Toshiba Corporation P-type doping layers for use with light emitting devices
US8664679B2 (en) 2011-09-29 2014-03-04 Toshiba Techno Center Inc. Light emitting devices having light coupling layers with recessed electrodes
US8853668B2 (en) 2011-09-29 2014-10-07 Kabushiki Kaisha Toshiba Light emitting regions for use with light emitting devices
US20160233399A1 (en) * 2013-11-07 2016-08-11 Toshiba Hokuto Electronics Corporation Light emitting device
US9799811B2 (en) * 2013-11-07 2017-10-24 Toshiba Hokuto Electronics Corporation Light emitting device

Also Published As

Publication number Publication date
CN100376042C (en) 2008-03-19
CN1612368A (en) 2005-05-04
US20050093428A1 (en) 2005-05-05
JP2005159299A (en) 2005-06-16
TW200520264A (en) 2005-06-16
TWI302383B (en) 2008-10-21

Similar Documents

Publication Publication Date Title
US7247985B2 (en) Semiconductor light-emitting device having annular shape light emitting region and current blocking layer
KR102453206B1 (en) Light emitting diode and manufacturing method thereof
US7683391B2 (en) UV emitting LED having mesa structure
US6316792B1 (en) Compound semiconductor light emitter and a method for manufacturing the same
US7157294B2 (en) Group III nitride compound semiconductor light-emitting element
US6121635A (en) Semiconductor light-emitting element having transparent electrode and current blocking layer, and semiconductor light-emitting including the same
KR102437828B1 (en) Semiconductor light emitting device and manufacturing method thereof
JP7284188B2 (en) Micron size light emitting diode design
US8044439B2 (en) Light-emitting device and manufacturing method of the same
JP5169012B2 (en) Semiconductor light emitting device
JP2006108698A (en) Contact for flip-chip light-emitting device and omnidirectional reflecting mirror
JP2003017757A (en) Flip-chip semiconductor light emitting element
US11894502B2 (en) Method of manufacturing semiconductor optical device and intermediate article of semiconductor optical device
JP2002353499A (en) Semiconductor light-emitting device
JPH10173224A (en) Compound semiconductor light emitting element and its manufacture
US7884381B2 (en) Light emitting device and method for fabricating the same including a back surface electrode with an Au alloy
JP4911347B2 (en) Semiconductor light emitting device
WO2013084867A1 (en) Light-emitting diode and method for manufacturing same
JP2004186544A (en) Semiconductor light emitting element
JPH07176788A (en) Light emitting diode
TW202046515A (en) Infrared led device
JP4127045B2 (en) Semiconductor light emitting device
JP2002368273A (en) Semiconductor light-emitting device
JP2001085742A (en) Semiconductor light emitting element and its manufacturing method
US7482634B2 (en) Monolithic array for solid state ultraviolet light emitters

Legal Events

Date Code Title Description
AS Assignment

Owner name: SHARP KABUSHIKI KAISHA, JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:KANEKO, KAZUAKI;UMEDA, HIROSHI;SASAKI, KAZUAKI;AND OTHERS;REEL/FRAME:015921/0899

Effective date: 20040928

STCF Information on status: patent grant

Free format text: PATENTED CASE

FEPP Fee payment procedure

Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

FPAY Fee payment

Year of fee payment: 4

FEPP Fee payment procedure

Free format text: PAYER NUMBER DE-ASSIGNED (ORIGINAL EVENT CODE: RMPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

AS Assignment

Owner name: XIAMEN SAN'AN OPTOELECTRONICS CO., LTD., CHINA

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:SHARP KABUSHIKI KAISHA;REEL/FRAME:034130/0632

Effective date: 20140908

FPAY Fee payment

Year of fee payment: 8

MAFP Maintenance fee payment

Free format text: PAYMENT OF MAINTENANCE FEE, 12TH YEAR, LARGE ENTITY (ORIGINAL EVENT CODE: M1553); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

Year of fee payment: 12